Robots.txt Code check

[hayem]

I am using this code on my site.I have added this under root.

User-Agent: *
Allow: /

User-Agent: msnbot
Disallow: /ppc/
Allow: /

User-Agent: Slurp
Disallow: /ppc/
Allow: /

User-Agent: Googlebot
Disallow: /ppc/
Allow: / 

trying to exclude ppc folder from search engines.is this correct?

2-also i have a subdomain in which i do not want search engines crawling.I have added this 2nd robots.txt under subdomain.maindomain.com

User-Agent: *
Disallow: / 

will these 2 robots.txt work?

thank you